Well I just went out for a ride today to try out the new sprockets. I noticed that with my bike running, the speedometer jumps to 10 mph while sitting still and if I rev the motor, the odometer starts to roll itself to the next set of numbers- if it is at 100 miles, it will roll to 099 or something like that. Well after pacing myself next to my buddy at 55, my speedo is reading 75. Any reasons as to why, the bike had a 53 tooth rear sprocket and stock front for stunting but I changed it back to stock 43 tooth. I can see the 10 mph due to the starting and sitting still it showing 10 mph but why off 10 more- it is stock with nothing done to alter the speedo. Also why does the odometer jump when reving- What should I look for?